It is generally known from the prior art that the material flow between individual work stations, for example in a filling and packaging facility, is decoupled by storage devices or storage tables. Such a storage device is e.g. provided downstream of a filling machine and upstream of a packaging machine. With the help of the storage device it is possible to prevent a complete standstill of the filling and packaging facility in the event of a short malfunction of the packaging machine. In this case the products supplied by the filling machine are temporarily stored by the storage device. Therefore, the products can be continuously transported in a facility even in the case of operating speeds varying at individual work stations.
DE 25 04 264 A1 discloses a storage device having a first feed path, a storage path and a second feed path provided between the first feed path and the storage path. In this known storage device, the products are transported during normal operation just via the first feed path from a first end with an inlet to a second end of said storage device having an outlet. Hence, during normal operation of the storage device the second feed path and the storage path are deactivated, and the products are moved in a straight movement through said known storage device. In the event of malfunctions of a work station that is arranged downstream of the storage device, the product is accumulated at the end of the storage device comprising the outlet because the first feed path of the storage device is still operated and further products are fed to the storage device from an upstream work station to said device. The accumulated products are transferred via an inlet opening provided laterally relative to the first feed path near the inlet of the storage device to the second feed path and the storage path. A reservoir is thereby built up next to the first feed path. The storage device is now operated such that the second feed path and the storage path are also activated. Hence, the storage path according to this known device has only a function during the storing operation of the storage device. The products are transported via the storage path and the second feed path towards the outlet of the storage device. As soon as the downstream work station is operated again under normal operational conditions, the products stored on the storage path and on the second feed path will be discharged. After the reservoir has been emptied and a dynamic equilibrium has been reached, the second feed path and the storage path are again deactivated.
The prior art also discloses storage devices in the case of which the storage path is operated both during normal operation and during storage operation of the storage device. Such a device is known from EP 1 144 285 B1, which is regarded as generic for the method and the device of the present disclosure.
EP 1 144 285 B1 discloses a storage device in which storage paths are provided on both sides of a feed path. The feed path and the storage paths according to this known device are thus configured to be alternating. In contrast to the storage device known from DE 25 04 264 A1, the output rate of the products during normal operation of the storage device also depends on the speed of the storage path in the storage device according to EP 1 144 285 B1.
Although the device known from EP 1 144 285 B1 offers the advantage that operational variations in the upstream work station can be offset for a short period of time, the control efforts required for this known storage device are great, the reason being that reservoirs are formed at both sides of the feed path. In a storage device with e.g. two feed paths, three different reservoirs are thus built up.
In case of a malfunction in this storage device, which malfunction is e.g. caused by a product that has been tilted in the storage path between the two feed paths, it is only under considerable efforts that said product can be put upright again. Since the storage path is enclosed by the two feed paths, an operator's access to the reservoir between said two feed paths is limited. Moreover, since a multitude of reservoirs are alternately formed with respect to the feed paths according to this known storage device, it is complicated to monitor the respective reservoirs for rapidly detecting and eliminating malfunctions.
A storage device based on a similar constructional principle as the above-mentioned storage device known from EP 1 144 285 B1 is known from EP 1 380 522 B1. In the storage device according to EP 1 380 522 B1 a storage path is also provided on both sides of a feed path. Said known storage device is thereby subject to the same drawbacks as the storage device known from EP 1 144 285 B1.